Publications by authors named "Yadong Li"

420 Publications

An Efficient Virus-Induced Gene Silencing System for Functional Genomics Research in Walnut ( L.) Fruits.

Front Plant Sci 2021 23;12:661633. Epub 2021 Jun 23.

College of Life Sciences, Northwest A&F University, Yangling, China.

The Persian walnut ( L.) is a leading source of woody oil in warm temperate regions and has high nutritional and medicinal values. It also provides both tree nuts and woody products. Nevertheless, incomplete characterization of the walnut genetic system limits the walnut gene function analysis. This study used the tobacco rattle virus (TRV) vector to construct an infectious pTRV- recombinant clone. A co-culture inoculation method utilizing was screened out from four inoculation methods and optimized to set up an efficient virus-induced gene silencing (VIGS) system for fruit. The optimized VIGS-TRV system induced complete photobleaching phenotype on the walnut fruits of four cultivars, and the transcript levels decreased by up to 88% at 8 days post-inoculation (dpi). While those of browning-related polyphenol oxidase (PPO) genes and decreased by 67 and 80% at 8 dpi, respectively, accompanied by a significant reduction in fruit browning phenotype. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis screening and Western Blot showed that the PPO protein levels were significantly reduced. Moreover, a model of TRV-mediated VIGS system for inoculating fruit with efficient silence efficiency co-culture was developed. These results indicate that the VIGS-TRV system is an efficient tool for rapid gene function analysis in fruits.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2021.661633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8261060PMC
June 2021

Fabricating polyoxometalates-stabilized single-atom site catalysts in confined space with enhanced activity for alkynes diboration.

Nat Commun 2021 Jul 9;12(1):4205. Epub 2021 Jul 9.

Department of Chemistry, Tsinghua University, Beijing, China.

Effecting the synergistic function of single metal atom sites and their supports is of great importance to achieve high-performance catalysts. Herein, we successfully fabricate polyoxometalates (POMs)-stabilized atomically dispersed platinum sites by employing three-dimensional metal-organic frameworks (MOFs) as the finite spatial skeleton to govern the accessible quantity, spatial dispersion, and mobility of metal precursors around each POM unit. The isolated single platinum atoms (Pt) are steadily anchored in the square-planar sites on the surface of monodispersed Keggin-type phosphomolybdic acid (PMo) in the cavities of various MOFs, including MIL-101, HKUST-1, and ZIF-67. In contrast, either the absence of POMs or MOFs yielded only platinum nanoparticles. [email protected] are seven times more active than the corresponding nanoparticles in the diboration of phenylacetylene, which can be attributed to the synergistic effect of the preconcentration of organic reaction substrates by porous MOFs skeleton and the decreased desorption energy of products on isolated Pt atom sites.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-021-24513-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8271022PMC
July 2021

Rational Design of Single-Atom Site Electrocatalysts: From Theoretical Understandings to Practical Applications.

Adv Mater 2021 Jul 8:e2008151. Epub 2021 Jul 8.

Department of Chemistry, Tsinghua University, Beijing, 100084, China.

Atomically dispersed metal-based electrocatalysts have attracted increasing attention due to their nearly 100% atomic utilization and excellent catalytic performance. However, current fundamental comprehension and summaries to reveal the underlying relationship between single-atom site electrocatalysts (SACs) and corresponding catalytic application are rarely reported. Herein, the fundamental understandings and intrinsic mechanisms underlying SACs and corresponding electrocatalytic applications are systemically summarized. Different preparation strategies are presented to reveal the synthetic strategies with engineering the well-defined SACs on the basis of theoretical principle (size effect, metal-support interactions, electronic structure effect, and coordination environment effect). Then, an overview of the electrocatalytic applications is presented, including oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, oxidation of small organic molecules, carbon dioxide reduction reaction, and nitrogen reduction reaction. The underlying structure-performance relationship between SACs and electrocatalytic reactions is also discussed in depth to expound the enhancement mechanisms. Finally, a summary is provided and a perspective supplied to demonstrate the current challenges and opportunities for rational designing, synthesizing, and modulating the advanced SACs toward electrocatalytic reactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.202008151DOI Listing
July 2021

Propranolol vs. steroids in the treatment of infantile hemangiomas: A meta-analysis.

Mol Clin Oncol 2021 Aug 10;15(2):156. Epub 2021 Jun 10.

Department of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.

Infantile hemangioma (IH) is a common disease, and drug therapy is the most common treatment method. Clinically, steroids have long been used as first-line drugs, but in recent years, some doctors have begun to use propranolol to treat infantile hemangiomas (IHs). The present study performed a meta-analysis to evaluate the clinical effects of propranolol in comparison with steroids in the treatment of infantile hemangiomas. A detailed review of the literature on PubMed, Cochrane Library, Embase and Web of Science was performed prior to March 31, 2020. All literatures were compared with the clinical effects of propranolol and steroids in the treatment of infantile hemangiomas. A total of two researchers independently screened the literature according to the selection criteria, extracted data and assessed the risk of bias for the included studies. Review Manager 5.3 was used to meta-analyze all the included studies. According to the selection criteria, nine articles were included in the present study. The meta-analysis revealed that the effective rate of propranolol was greater than that of steroids in treating infantile hemangiomas [odds ratio (OR), 3.96, 95% confidence interval (CI), 2.47-6.37; P<0.00001]. Additionally, propranolol had fewer complications than steroids (OR, 0.21; 95% CI, 0.12-0.36; P<0.00001). The recurrence rate of the two groups was not statistically different (OR, 1.83; 95% CI, 0.59-5.70; P=0.3) and the surgical resection rate of propranolol was lower than steroids (OR, 0.19; 95% CI, 0.08-0.46; P=0.0002). The present study demonstrated that propranolol is more effective than steroids for the treatment of IHs, and provides a theoretical basis for the clinical use of propranolol as an alternative to steroids.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3892/mco.2021.2318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8220686PMC
August 2021

The atomic-level regulation of single-atom site catalysts for the electrochemical CO reduction reaction.

Chem Sci 2021 Feb 20;12(12):4201-4215. Epub 2021 Feb 20.

Department of Chemistry, Tsinghua University Beijing 100084 China

The electrochemical CO reduction reaction (CORR) is viewed as a promising way to remove the greenhouse gas CO from the atmosphere and convert it into useful industrial products such as methane, methanol, formate, ethanol, and so forth. Single-atom site catalysts (SACs) featuring maximum theoretical atom utilization and a unique electronic structure and coordination environment have emerged as promising candidates for use in the CORR. The electronic properties and atomic structures of the central metal sites in SACs will be changed significantly once the types or coordination environments of the central metal sites are altered, which appears to provide new routes for engineering SACs for CO electrocatalysis. Therefore, it is of great importance to discuss the structural regulation of SACs at the atomic level and their influence on CORR activity and selectivity. Despite substantial efforts being made to fabricate various SACs, the principles of regulating the intrinsic electrocatalytic performances of the single-atom sites still needs to be sufficiently emphasized. In this perspective article, we present the latest progress relating to the synthesis and catalytic performance of SACs for the electrochemical CORR. We summarize the atomic-level regulation of SACs for the electrochemical CORR from five aspects: the regulation of the central metal atoms, the coordination environments, the interface of single metal complex sites, multi-atom active sites, and other ingenious strategies to improve the performance of SACs. We highlight synthesis strategies and structural design approaches for SACs with unique geometric structures and discuss how the structure affects the catalytic properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0sc07040hDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8179652PMC
February 2021

Tandem catalyzing the hydrodeoxygenation of 5-hydroxymethylfurfural over a NiFe intermetallic supported Pt single-atom site catalyst.

Chem Sci 2021 Jan 29;12(11):4139-4146. Epub 2021 Jan 29.

Department of Chemistry, Tsinghua University Beijing 100084 China

Single-atom site catalysts (SACs) have been used in multitudinous reactions delivering ultrahigh atom utilization and enhanced performance, but it is challenging for one single atom site to catalyze an intricate tandem reaction needing different reactive sites. Herein, we report a robust SAC with dual reactive sites of isolated Pt single atoms and the NiFe intermetallic support (Pt/NiFe IMC) for tandem catalyzing the hydrodeoxygenation of 5-hydroxymethylfurfural (5-HMF). It delivers a high catalytic performance with 99.0% 5-HMF conversion in 30 min and a 2, 5-dimethylfuran (DMF) yield of 98.1% in 90 min at a low reaction temperature of 160 °C, as well as good recyclability. These results place Pt/NiFe IMC among the most active catalysts for the 5-HMF hydrodeoxygenation reaction reported to date. Rational control experiments and first-principles calculations confirm that Pt/NiFe IMC can readily facilitate the hydrodeoxygenation reaction by a tandem mechanism, where the single Pt site accounts for C[double bond, length as m-dash]O group hydrogenation and the NiFe interface promotes the C-OH bond cleavage. This interfacial tandem catalysis over the Pt single-atom site and NiFe IMC support may develop new opportunities for the rational structural design of SACs applied in other heterogeneous tandem reactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0sc05983hDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8179463PMC
January 2021

An Adjacent Atomic Platinum Site Enables Single-Atom Iron with High Oxygen Reduction Reaction Performance.

Angew Chem Int Ed Engl 2021 Jun 22. Epub 2021 Jun 22.

Department of Chemistry, Tsinghua University, Beijing, 100084, China.

The modulation effect has been widely investigated to tune the electronic state of single-atomic M-N-C catalysts to enhance the activity of oxygen reduction reaction (ORR). However, the in-depth study of modulation effect is rarely reported for the isolated dual-atomic metal sites. Now, the catalytic activities of Fe-N moiety can be enhanced by the adjacent Pt-N moiety through the modulation effect, in which the Pt-N acts as the modulator to tune the 3d electronic orbitals of Fe-N active site and optimize ORR activity. Inspired by this principle, we design and synthesize the electrocatalyst that comprises isolated Fe-N /Pt-N moieties dispersed in the nitrogen-doped carbon matrix (Fe-N /Pt-N @NC) and exhibits a half-wave potential of 0.93 V vs. RHE and negligible activity degradation (ΔE =8 mV) after 10000 cycles in 0.1 M KOH. We also demonstrate that the modulation effect is not effective for optimizing the ORR performances of Co-N /Pt-N and Mn-N /Pt-N systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202105186DOI Listing
June 2021

The Electronic Metal-Support Interaction Directing the Design of Single Atomic Site Catalysts: Achieving High Efficiency Towards Hydrogen Evolution.

Angew Chem Int Ed Engl 2021 Jun 21. Epub 2021 Jun 21.

Department of Chemistry, Tsinghua University, Beijing, 100084, China.

It is still of great difficulty to develop the non-platinum catalyst with high catalytic efficiency towards hydrogen evolution reaction via the strategies till now. Therefore, it is necessary to develop the new methods of catalyst designing. Here, we put forward the catalyst designed by the electronic metal-support interaction (EMSI), which is demonstrated to be a reliable strategy to find out the high-efficiency catalyst. We carried out the density functional theory calculation first to design the proper EMSI of the catalyst. We applied the model of M1-M2-X (X=C, N, O) during the calculation. Among the catalysts we chose, the EMSI of Rh1TiC, with the active sites of Rh1-Ti2C2, is found to be the most proper one for HER. The electrochemical experiment further demonstrated the feasibility of the EMSI strategy. The single atomic site catalyst of Rh1-TiC exhibits higher catalytic efficiency than that of state-of-art Pt/C. It achieves a small overpotential of 22 mV and 86 mV at the at the current density of 10 mA cm and 100 mA cm in acid media, with a Tafel slope of 25 mV dec and a mass activity of 54403.9 mA cm  mg (vs. 192.2 mA cm  mg of Pt/C). Besides, it also shows appealing advantage in energy saving compared with Pt/C (≈20 % electricity consuming decrease at 2 kA m ) Therefore, we believe that the strategy of regulating EMSI can act as a possible way for achieving the high catalytic efficiency on the next step of SACs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202107123DOI Listing
June 2021

Atomically Dispersed Pt-NC Sites Enabling Efficient and Selective Electrocatalytic C-C Bond Cleavage in Lignin Models under Ambient Conditions.

J Am Chem Soc 2021 Jun 17;143(25):9429-9439. Epub 2021 Jun 17.

Department of Chemistry, Tsinghua University, Beijing 100084, China.

Selective cleavage of C-C linkages is the key and a challenge for lignin degradation to harvest value-added aromatic compounds. To this end, electrocatalytic oxidation presents a promising technique by virtue of mild reaction conditions and strong sustainability. However, the existing electrocatalysts (traditional bulk metal and metal oxides) for C-C bond oxidative cleavage suffer from poor selectivity and low product yields. We show for the first time that atomically dispersed Pt-NC sites planted on nitrogen-doped carbon nanotubes (Pt/N-CNTs), constructed via a stepwise polymerization-carbonization-electrostatic adsorption strategy, are highly active and selective toward C-C bond cleavage in β-O-4 model compounds under ambient conditions. Pt/N-CNTs exhibits 99% substrate conversion with 81% yield of benzaldehyde, which is exceptional and unprecedented compared with previously reported electrocatalysts. Moreover, Pt/N-CNTs using only 0.41 wt % Pt achieved a much higher benzaldehyde yield than those of the state-of-the-art bulk Pt electrode (100 wt % Pt) and commercial Pt/C catalyst (20 wt % Pt). Systematic experimental investigation together with density functional theory (DFT) calculation suggests that the superior performance of Pt/N-CNTs arises from the atomically dispersed Pt-NC sites facilitating the formation of a key C radical intermediate, further inducing a radical/radical cross-coupling path to break the C-C bond. This work opens up opportunities in lignin valorization via a green and sustainable electrochemical route with ultralow noble metal usage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.1c02328DOI Listing
June 2021

miR-141-5p suppresses vascular smooth muscle cell inflammation, proliferation, and migration via inhibiting the HMGB1/NF-κB pathway.

J Biochem Mol Toxicol 2021 Jun 14:e22828. Epub 2021 Jun 14.

Department of Pharmacy, Shanxi Cancer Hospital, Taiyuan, Shanxi, China.

MicroRNAs (miRNAs) have been identified as significant modulators in the pathogenesis of atherosclerosis (AS). Additionally, the dysregulation of vascular smooth muscle cells (VSMCs) is a crucial biological event during AS. Our study aimed to explore the functional roles and molecular mechanisms of miR-141-5p in VSMCs dysfunction. C57BL/6 mice were used to establish AS animal model. Human VSMCs were treated by oxidized low-density lipoprotein (ox-LDL) to establish AS cell model. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to probe miR-141-5p and high-mobility group box 1 (HMGB1) mRNA expressions in VSMCs or plasma samples of the mice. Inflammatory cytokines were detected by enzyme-linked immunosorbent assay kits. Cell counting kit-8 and bromodeoxyuridine assays were performed to evaluate cell proliferation. Cell migration and apoptosis were detected with Transwell assay and flow cytometry analysis, respectively. The target gene of miR-141-5p was predicted with the TargetScan database, and the interaction between miR-141-5p and HMGB1/nuclear factor-κB (NF-κB) was further validated by dual-luciferase reporter assay, qRT-PCR, and Western blot analysis. miR-141-5p was found to be decreased in the plasma of patients and mice model with AS. Its expression was also downregulated in VSMCs treated by ox-LDL. miR-141-5p overexpression inhibited the inflammation, proliferation, migration of VSMCs, and promoted the apoptosis of VSMCs. HMGB1 was identified as a direct target of miR-141-5p, and miR-141-5p could repress the activity of HMGB1/NF-κB signaling. HMGB1 restoration reversed the effects of miR-141-5p, and NF-κB inhibitor JSH-23 showed similar effects with miR-141-5p mimics. miR-141-5p inhibits VSMCs' dysfunction by targeting the HMGB1/NF-κB pathway, which probably functions as a protective factor during the development of AS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbt.22828DOI Listing
June 2021

In Situ Implanting of Single Tungsten Sites into Defective UiO-66(Zr) by Solvent-Free Route for Efficient Oxidative Desulfurization at Room Temperature.

Angew Chem Int Ed Engl 2021 Jun 13. Epub 2021 Jun 13.

Department of Chemistry, Tsinghua University, Beijing, 100084, China.

Design of single-site catalysts with catalytic sites at atomic-scale and high atom utilization, provides new opportunities to gain superior catalytic performance for targeted reactions. In this contribution, we report a one-pot green approach for in situ implanting of single tungsten sites (up to 12.7 wt.%) onto the nodes of defective UiO-66(Zr) structure via forming Zr-O-W bonds under solvent-free condition. The catalysts displayed extraordinary activity for the oxidative removal of sulfur compounds (1000 ppm S) at room temperature within 30 min. The turnover frequency (TOF) value can reach 44.0 h at 30 °C, which is 109.0, 12.3 and 1.2 times higher than that of pristine UiO-66(Zr), WO , and WCl (homogeneous catalyst). Theoretical and experimental studies show that the anchored W sites can react with oxidant readily and generate W -peroxo intermediates that determine the reaction activity. Our work not only manifests the application of SSCs in the field of desulfurization of fuel oil but also opens a new solvent-free avenue for fabricating MOFs based SSCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202107018DOI Listing
June 2021

Dual-atom Pt heterogeneous catalyst with excellent catalytic performances for the selective hydrogenation and epoxidation.

Nat Commun 2021 May 26;12(1):3181. Epub 2021 May 26.

Department of Chemistry, Tsinghua University, Beijing, China.

Atomically monodispersed heterogeneous catalysts with uniform active sites and high atom utilization efficiency are ideal heterogeneous catalytic materials. Designing such type of catalysts, however, remains a formidable challenge. Herein, using a wet-chemical method, we successfully achieved a mesoporous graphitic carbon nitride (mpg-CN) supported dual-atom Pt catalyst, which exhibited excellent catalytic performance for the highly selective hydrogenation of nitrobenzene to aniline. The conversion of ˃99% is significantly superior to the corresponding values of mpg-CN-supported single Pt atoms and ultra-small Pt nanoparticles (~2 nm). First-principles calculations revealed that the excellent and unique catalytic performance of the Pt species originates from the facile H dissociation induced by the diatomic characteristics of Pt and the easy desorption of the aniline product. The produced Pt/mpg-CN samples are versatile and can be applied in catalyzing other important reactions, such as the selective hydrogenation of benzaldehyde and the epoxidation of styrene.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-021-23517-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8155026PMC
May 2021

Manganese vacancy-confined single-atom Ag in cryptomelane nanorods for efficient Wacker oxidation of styrene derivatives.

Chem Sci 2021 Mar 16;12(17):6099-6106. Epub 2021 Mar 16.

Department of Chemistry, Tsinghua University Beijing 100084 China

Single-atom catalysts provide a pathway to elucidate the nature of catalytically active sites. However, keeping them stabilized during operation proves to be challenging. Herein, we employ cryptomelane-type octahedral molecular sieve nanorods featuring abundant manganese vacancy defects as a support, to periodically anchor single-atom Ag. The doped Ag atoms with tetrahedral coordination are found to locate at cation substitution sites rather than being supported on the catalyst surface, thus effectively tuning the electronic structure of adjacent manganese atoms. The resulting unique Ag-O-MnO unit functions as the active site. Its turnover frequency reaches 1038 h, one order of magnitude higher than for previously reported catalysts, with 90% selectivity for anti-Markovnikov phenylacetaldehyde. Mechanistic studies reveal that the activation of styrene on the ensemble site of Ag-O-MnO is significantly promoted, which can accelerate the oxidation of styrene and, in particular, the rate-determining step of forming the epoxide intermediate. Such an extraordinary electronic promotion can be extended to other single-atom catalysts and paves the way for their practical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d1sc00700aDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8098698PMC
March 2021

Tianlongkechuanling Inhibits Pulmonary Fibrosis Through Down-Regulation of Arginase-Ornithine Pathway.

Front Pharmacol 2021 22;12:661129. Epub 2021 Apr 22.

Traditional Chinese Medicine, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.

Pulmonary Fibrosis (PF) is an interstitial lung disease characterized by excessive accumulation of extracellular matrix in the lungs, which disrupts the structure and gas exchange of the alveoli. There are only two approved therapies for PF, nintedanib (Nib) and pirfenidone. Therefore, the use of Chinese medicine for PF is attracting attention. Tianlongkechuanling (TL) is an effective Chinese formula that has been applied clinically to alleviate PF, which can enhance lung function and quality of life. The potential effects and specific mechanisms of TL have not been fully explored, yet. In the present study, proteomics was performed to explore the therapeutic protein targets of TL on Bleomycin (BLM)-induced Pulmonary Fibrosis. BLM-induced PF mice models were established. Hematoxylineosin staining and Masson staining were used to analyze histopathological changes and collagen deposition. To screen the differential proteins expression between the Control, BLM, BLM + TL and BLM + Nib (BLM + nintedanib) groups, quantitative proteomics was performed using tandem mass tag (TMT) labeling with nanoLC-MS/MS [nano liquid chromatographymass spectrometry]). Changes in the profiles of the expressed proteins were analyzed using the bioinformatics tools Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The protein-protein interactions (PPI) were established by STRING. Expressions of α-smooth muscle actin (α-SMA), (), () and enzymes in arginase-ornithine pathway were detected by Western blot or RT-PCR. TL treatments significantly ameliorated BLM-induced collagen deposition in lung tissues. Moreover, TL can inhibit the protein expressions of α-SMA and the mRNA expressions of and . Using TMT technology, we observed 253 differentially expressed proteins related to PPI networks and involved different KEGG pathways. Arginase-ornithine pathway is highly significant. The expression of Arg was significantly decreased after TL treatments. Administration of TL in BLM-induced mice resulted in decreasing pulmonary fibrosis. Our findings propose that the down regulation of arginase-ornithine pathway expression with the reduction of arginase biosynthesis is a central mechanism and potential treatment for pulmonary fibrosis with the prevention of TL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphar.2021.661129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8114272PMC
April 2021

Red, orange, yellow and green luminescence by carbon dots: hydrogen-bond-induced solvation effects.

Nanoscale 2021 Apr 26;13(14):6846-6855. Epub 2021 Mar 26.

Key Laboratory for Biobased Materials and Energy of Ministry of Education/Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, College of Materials and Energy, South China Agricultural University, Guangzhou, 510642, China.

The mechanism of the solvation-dependent multicolor luminescence of carbon dots (CDs) is not clear, despite the fact that multicolor luminescent CDs have important applications in many fields. In this article, we report solvated chromogenic CDs with productivity of up to 57%. The luminescence of the CD particles exhibits a regular redshift in N,N-dimethylformamide (DMF), ethanol, water, and acetic acid. The redshift of the CDs may be ascribed to the linking of the CD surfaces to the solvent through hydrogen bonds (HB). Different surface level states are formed by HB between the surfaces of the CDs and the solvent, and differences in dispersion states lead to different energy resonance transfer (ETR) efficiencies. The CDs/BO composite exhibits excellent fluorescence thermal stability, and it has also been used to manufacture white-light-emitting devices with a high color rendering index of 87. Additionally, the excellent solvation effects of the CDs have application prospects in the detection of the water content in organic solvents. Finally, the CDs are used to realize cell imaging and positioning, which has significant application prospects in biological fields.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0nr08128kDOI Listing
April 2021

A Supported Pd Dual-Atom Site Catalyst for Efficient Electrochemical CO Reduction.

Angew Chem Int Ed Engl 2021 Jun 6;60(24):13388-13393. Epub 2021 May 6.

Department of Chemistry, Tsinghua University, Beijing, 100084, PR China.

Dual-atom site catalysts (DACs) have emerged as a new frontier in heterogeneous catalysis because the synergistic effect between adjacent metal atoms can promote their catalytic activity while maintaining the advantages of single-atom site catalysts (SACs), like 100 % atomic utilization efficiency and excellent selectivity. Herein, a supported Pd DAC was synthesized and used for electrochemical CO reduction reaction (CO RR) for the first time. The as-obtained Pd DAC exhibited superior CO RR catalytic performance with 98.2 % CO faradic efficiency at -0.85 V vs. RHE, far exceeding that of Pd SAC, and coupled with long-term stability. The density functional theory (DFT) calculations revealed that the intrinsic reason for the superior activity of Pd DAC toward CO RR was the electron transfer between Pd atoms at the dimeric Pd sites. Thus, Pd DAC possessed moderate adsorption strength of CO*, which was beneficial for CO production in CO RR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202101559DOI Listing
June 2021

Coupling Relation between the Location of Cross-Cut Negative Pressure and Injecting Nitrogen into Coal Mine Goaf.

ACS Omega 2021 Mar 17;6(12):8189-8198. Epub 2021 Mar 17.

CCTEG Shenyang Research Institute, Shenyang 110000, China.

Injecting nitrogen into goaf has been widely adopted for preventing fire hazards in coal mines. In this paper, the coupling relation between different locations of negative pressure of cross-cut drainage and nitrogen injection was investigated. The minefield data collection was carried out by an in situ beam tube system on the intake airway and return airway of the mine goaf. The validated Computational Fluid Dynamics (CFD) model that was secondarily modified by on-site collected data was applied for further research. It is demonstrated that the area of the spontaneous combustion zone generally shows a sharp decline first, then tends to stabilize, and finally has a slight drop and rise with the increasing nitrogen injection time. It is obvious that the location of the negative pressure of cross-cut exerts a significant influence on the optimal nitrogen injection location and time. When the cross-cut is located in the center of the air leakage zone, spontaneous combustion zone, and asphyxiation zone of goaf, the optimal nitrogen injection location and time correspond to the P (25 m, 1200 min), P (30 m, 120 min), and P (35m, 1800 min), respectively. According to the simulation result, the specific relation between the optimal nitrogen injection point () and the distance from the working distance of the cross-cut () by Newton interpolation polynomial analysis was figured out and verified that () = 24.70808 + 0.293356 - 0.001436 . It is hoped that the result can provide scientific guidance for coal mine fire prevention and control with nitrogen injection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.0c06222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8014926PMC
March 2021

Physiological and biochemical effects of TiAlC nanosheets on rice (Oryza sativa L.).

Sci Total Environ 2021 May 23;770:145340. Epub 2021 Jan 23.

Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou 510650, China. Electronic address:

MAX phase materials are a new type of nanomaterial with wide applications, but the potential effects of MAX phase materials on plants have not been reported. Herein, we selected TiAlC nanosheets as a typical MAX phase material to investigate its potential impacts on rice (Oryza sativa L.) at 0-1000 μg·mL. The foliar application of TiAlC at 100 and 1000 μg·mL inhibited the growth of rice seedlings by producing excess reactive oxygen species (ROS). Furthermore, foliar spraying of TiAlC at 100 μg·mL decreased the stomatal aperture (78.6%) and increased the number of trichomes (100%). These responses demonstrated that the application of TiAlC could interfere with the immune system of plants by changing the structure and function of leaves, disturbing the activities of antioxidant enzymes. According to the above results, we concluded that the toxicity of TiAlC nanosheets on plants was mainly caused by the release of titanium ions. This study provides a valuable reference for understanding the impact of MAX phase materials on plants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2021.145340DOI Listing
May 2021

CircGDI2 Regulates the Proliferation, Migration, Invasion and Apoptosis of OSCC via miR-454-3p/FOXF2 Axis.

Cancer Manag Res 2021 11;13:1371-1382. Epub 2021 Feb 11.

Department of Oral Medicine Centre, Henan Provincial People's Hospital, Zhengzhou, Henan, People's Republic of China.

Background: Aberrant expression of circular RNA (circRNA) is involved in the occurrence and development of multifarious cancers, including oral squamous cell carcinoma (OSCC). However, the biological role of circGDI2 and the action mechanism in OSCC remain largely unclear.

Methods: The expression levels of circGDI2, miR-454-3p and forkhead box F2 (FOXF2) were examined by quantitative real-time PCR (qRT-PCR) or Western blot. The stability of circGDI2 was confirmed by Ribonuclease R (RNase R) assay. Cell Counting Kit 8 (CCK8) assay, colony formation and transwell assay were used to detect cell proliferation, migration or invasion. Cell apoptosis was tested by flow cytometry. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to verify the interaction between miR-454-3p and circGDI2 or FOXF2. Moreover, xenograft mouse models were constructed to assess tumor growth in vivo.

Results: CircGDI2 was a stable circRNA and was low expressed in OSCC tissues and cells. CircGDI2 overexpression could effectively inhibit the proliferation, migration, invasion and promote apoptosis in OSCC cells, and suppress OSCC tumor growth in nude mice in vivo. MiR-454-3p could be sponged by circGDI2, and its overexpression could mitigate the suppressive effects of circGDI2 overexpression on OSCC progression. In addition, FOXF2 was a target of miR-454-3p, and miR-454-3p silence could impede the cell growth of OSCC cells by enhancing FOXF2 expression. Meanwhile, circGDI2 positively regulated FOXF2 expression by targeting miR-454-3p.

Conclusion: CircGDI2 served as a repressor to restrain OSCC malignancy via miR-454-3p/FOXF2 axis, which might be a novel biomarker for targeted OSCC therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/CMAR.S277096DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886390PMC
February 2021

A novel DNA and protein combination COVID-19 vaccine formulation provides full protection against SARS-CoV-2 in rhesus macaques.

Emerg Microbes Infect 2021 Dec;10(1):342-355

Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, People's Republic of China.

The current study aims to develop a safe and highly immunogenic COVID-19 vaccine. The novel combination of a DNA vaccine encoding the full-length Spike (S) protein of SARS-CoV-2 and a recombinant S1 protein vaccine induced high level neutralizing antibody and T cell immune responses in both small and large animal models. More significantly, the co-delivery of DNA and protein components at the same time elicited full protection against intratracheal challenge of SARS-CoV-2 viruses in immunized rhesus macaques. As both DNA and protein vaccines have been proven safe in previous human studies, and DNA vaccines are capable of eliciting germinal center B cell development, which is critical for high-affinity memory B cell responses, the DNA and protein co-delivery vaccine approach has great potential to serve as a safe and effective approach to develop COVID-19 vaccines that provide long-term protection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/22221751.2021.1887767DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7928010PMC
December 2021

Construction of Dual-Active-Site Copper Catalyst Containing both CuN and CuN Sites.

Small 2021 02 1;17(8):e2006834. Epub 2021 Feb 1.

Department of Chemistry, Tsinghua University, Beijing, 100084, China.

Clear recognition and rational construction of suitable active center for specific reaction is always of great significance in designing highly efficient catalysts. Herein, a dual-active-site copper catalyst (DAS-Cu) containing both CuN and CuN sites is reported. Such catalysts show extremely high catalytic performance (yield: up to 97%) toward oxyphosphorylation of alkenes, while catalysts with single active site (CuN or CuN ) are chemically inert in this reaction. Combined with theoretical and experimental results, the different roles of two different Cu active sites in this reaction are further identified. CuN site captures the oxygen and trigger further oxidizing process, while CuN site provides moderate adsorption sites for the protection of phosphonyl radicals. This work deeply discloses the significant cooperated role with two single-atomic sites in one catalytic active center and brings up a valuable clue for the rational design of better-performing heterogeneous catalyst.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.202006834DOI Listing
February 2021

One-step synthesis of single-site vanadium substitution in 1T-WS monolayers for enhanced hydrogen evolution catalysis.

Nat Commun 2021 Jan 29;12(1):709. Epub 2021 Jan 29.

Department of Chemistry, Tsinghua University, Beijing, 100084, China.

Metallic tungsten disulfide (WS) monolayers have been demonstrated as promising electrocatalysts for hydrogen evolution reaction (HER) induced by the high intrinsic conductivity, however, the key challenges to maximize the catalytic activity are achieving the metallic WS with high concentration and increasing the density of the active sites. In this work, single-atom-V catalysts (V SACs) substitutions in 1T-WS monolayers (91% phase purity) are fabricated to significantly enhance the HER performance via a one-step chemical vapor deposition strategy. Atomic-resolution scanning transmission electron microscopy (STEM) imaging together with Raman spectroscopy confirm the atomic dispersion of V species on the 1T-WS monolayers instead of energetically favorable 2H-WS monolayers. The growth mechanism of V [email protected] monolayers is experimentally and theoretically demonstrated. Density functional theory (DFT) calculations demonstrate that the activated V-atom sites play vital important role in enhancing the HER activity. In this work, it opens a novel path to directly synthesize atomically dispersed single-metal catalysts on metastable materials as efficient and robust electrocatalysts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-021-20951-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7846562PMC
January 2021

A general strategy to prepare atomically dispersed biomimetic catalysts based on host-guest chemistry.

Chem Commun (Camb) 2021 Feb 25;57(15):1895-1898. Epub 2021 Jan 25.

Department of Chemistry, School of Science, Beijing Jiaotong University, Beijing, 100044, P. R. China.

Herein, we report a general strategy based on host-guest interactions to fabricate atomically dispersed biomimetic catalysts, which were evaluated by diboration of phenylacetylene. The structure and function of these mimics are quite similar to those of enzymes, namely, the atomically dispersed metal serves as an active site, the external macromolecular structure plays a role as an enzyme catalytic pocket to stabilize the reaction intermediates and the interactions between the intermediates and functional groups near to the active site can reduce the reaction activation energy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0cc07119fDOI Listing
February 2021

Tuning the mechanical properties and degradation properties of polydioxanone isothermal annealing.

Turk J Chem 2020 26;44(5):1430-1444. Epub 2020 Oct 26.

Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu P.R. China.

Polydioxanone (PPDO) is synthesized by ring-opening polymerization of p-dioxanone, using stannous octoate as the catalyst. The polarized optical micrograph (POM) shows thes pherulite growth rate of PPDO decreases with an increase in the isothermal crystallization temperature. PPDO is compression-molded into bars, and PPDO bars are subjected to isothermal annealing at a range of temperatures (Ta = 50, 60, 70, 80, 90, and 100 °C), and correspond to three different annealing times (ta = 1h, 2h, 3h). The effect on PPDO is investigated by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). With an increase in Ta and ta, the grain size and the degree of crystallinity also increase. Meanwhile, the tensile strength is significantly improved. The PPDO bars (90 °C, 2 h) reach the maximum crystallinity (57.21%) and the maximum tensile strength (41.1 MPa). Interestingly, the heat treatment process does not result in serious thermal degradation. It is observed that the hydrolytic degradation of the annealed PPDO is delayed to some extent. Thus, annealed PPDO might have potential applications, particularly in the fields of orthopedic fixation and tissue engineering.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3906/kim-2006-55DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7754728PMC
October 2020

Obesity regulates miR-467/HoxA10 axis on osteogenic differentiation and fracture healing by BMSC-derived exosome LncRNA H19.

J Cell Mol Med 2021 Feb 20;25(3):1712-1724. Epub 2021 Jan 20.

Departmen of Orthopedics, Beijing Friendship Hospital, Capital Medical University, Beijing, China.

This study explored the therapeutic effect of bone marrow mesenchymal stem cell-derived exosomes on the treatment of obesity-induced fracture healing. Quantitative real-time PCR was used to detect the expression of lncRNA H19, miR-467 and Hoxa10 and combined with WB detection to detect osteogenic markers (RUNX2, OPN, OCN). Determine whether exosomes have entered BMSCs by immunofluorescence staining. Alkaline phosphatase (ALP) and alizarin red staining (ARS) staining were used to detect ALP activity and calcium deposition. We found that high-fat treatment can inhibit the secretion of BMSCs-derived exosomes and affect the expression of H19 carried by them. In vivo and in vitro experiments show that high-fat or obesity factors can inhibit the expression of osteogenic markers and reduce the staining activity of ALP and ARS. The treatment of exosomes from normal sources can reverse the phenomenon of osteogenic differentiation and abnormal fracture healing. Further bioinformatics analysis found that miR-467 as a regulatory molecule of lncRNA H19 and Hoxa10, and we verified the targeting relationship of the three through dual luciferase report experiments. Further, we found similar phenomena in ALP and ARS staining. Bone marrow mesenchymal stem cell-derived exosomes improve fracture healing caused by obesity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcmm.16273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7875915PMC
February 2021

Carbon-Supported Single-Atom Catalysts for Formic Acid Oxidation and Oxygen Reduction Reactions.

Small 2021 Apr 19;17(16):e2004500. Epub 2021 Jan 19.

Department of Chemistry, Tsinghua University, Beijing, 100084, China.

The commercialization of fuel cells, especially for direct formic acid fuel cells (DFAFCs) and proton-exchange membrane fuel cells (PEMFCs), is significantly restrained by the high cost, poor stability, and sluggish kinetics of platinum group metals (PGM) catalysts for both the anodic formic acid oxidation reaction (FAOR) and the cathodic oxygen reduction reaction (ORR). Currently, it has confronted with challenges, including exploring highly active, cost-effective, and stable catalysts to replace PGM for DFAFCs and PEMFCs. Recently, the increasing investigation has been focused on the single-atom catalysts (SACs) to enhance the catalytic performance owing to the maximum atom utilization and highly exposed active sites. The aim of this review is to present the recent research activities on carbon supported SACs. At the beginning of the review, metal-based SACs supported on different carbon supports, and the typical characterization methods are introduced. Subsequently, recent advances in metal-based SACs for FAOR and ORR catalysis are scientifically summarized. Particularly, some representative metal-based SACs for ORR activity are further exemplified with a deeper understanding of structure-activity relationships. Finally, the challenges and opportunities of SACs are prospected, such as the mechanism understanding and commercial applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.202004500DOI Listing
April 2021

Genome-wide identification and characterization of COMT gene family during the development of blueberry fruit.

BMC Plant Biol 2021 Jan 6;21(1). Epub 2021 Jan 6.

Engineering Center of Genetic Breeding and Innovative Utilization of Small Fruits of Jilin Province, College of Horticulture, Jilin Agricultural University, Changchun, 130118, China.

Background: Caffeic acid O-methyltransferases (COMTs) play an important role in the diversification of natural products, especially in the phenylalanine metabolic pathway of plant. The content of COMT genes in blueberry and relationship between their expression patterns and the lignin content during fruit development have not clearly investigated by now.

Results: Ninety-two VcCOMTs were identified in Vaccinium corymbosum. According to phylogenetic analyses, the 92 VcCOMTs were divided into 2 groups. The gene structure and conserved motifs within groups were similar which supported the reliability of the phylogenetic structure groupings. Dispersed duplication (DSD) and whole-genome duplication (WGD) were determined to be the major forces in VcCOMTs evolution. The results showed that the results of qRT-PCR and lignin content for 22 VcCOMTs, VcCOMT40 and VcCOMT92 were related to lignin content at different stages of fruit development of blueberry.

Conclusion: We identified COMT gene family in blueberry, and performed comparative analyses of the phylogenetic relationships in the 15 species of land plant, and gene duplication patterns of COMT genes in 5 of the 15 species. We found 2 VcCOMTs were highly expressed and their relative contents were similar to the variation trend of lignin content during the development of blueberry fruit. These results provide a clue for further study on the roles of VcCOMTs in the development of blueberry fruit and could promisingly be foundations for breeding blueberry clutivals with higher fruit firmness and longer shelf life.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12870-020-02767-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789564PMC
January 2021

Environmental investigation of bio-modification of steel slag through microbially induced carbonate precipitation.

J Environ Sci (China) 2021 Mar 9;101:282-292. Epub 2020 Sep 9.

Department of Civil and Architectural Engineering, Tennessee State University, Nashville, TN 37209, United States. Electronic address:

Steel slag (SS) is one of byproduct of steel manufacture industry. The environmental concerns of SS may limit their re-use in different applications. The goal of this study was to investigate the leaching behavior of metals from SS before and after treated by microbially induced carbonate precipitation (MICP). Toxicity characteristic leaching procedure, synthetic precipitation leaching procedure and water leaching tests were performed to evaluate the leaching behavior of major elements (Fe, Mg and Ca) and trace elements (Ba, Cu and Mn) in three scenarios. The concentrations of leaching metals increased with the content of SS. After it reached the peak concentration, the leaching concentration decreased with the content of SS. The leachability of all elements concerned in this study was below 0.5%. The carbonate generated from the MICP process contributed to the low leachability of metals. After bio-modified by MICP process, the leaching concentrations of Ba from TCLP, SPLP and WLT tests were below 2.0 mg/L, which was the limit in drinking water regulated by U.S. EPA. The concentrations of Cu leached out from MICP-treated SS-sand samples were below 1.3 mg/L which is the limit regulated by national secondary drinking water. Compared with the regulations of U.S.EPA and Mississippi Department of Environment Quality (MDEQ), MICP-treated samples were classified as non-hazardous materials with respects to the leaching of metals. Meanwhile, maximum contaminant limits regulated by U.S.EPA states that MICP-treated SS are eco-friendly materials that can be reused as construction materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jes.2020.08.023DOI Listing
March 2021

Silver Single-Atom Catalyst for Efficient Electrochemical CO Reduction Synthesized from Thermal Transformation and Surface Reconstruction.

Angew Chem Int Ed Engl 2021 Mar 29;60(11):6170-6176. Epub 2021 Jan 29.

Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.

We report an Ag single-atom catalyst (Ag /MnO ), which was synthesized from thermal transformation of Ag nanoparticles (NPs) and surface reconstruction of MnO . The evolution process of Ag NPs to single atoms is firstly revealed by various techniques, including in situ ETEM, in situ XRD and DFT calculations. The temperature-induced surface reconstruction process from the MnO (211) to (310) lattice plane is critical to firmly confine the existing surface of Ag single atoms; that is, the thermal treatment and surface reconstruction of MnO is the driving force for the formation of single Ag atoms. The as-obtained Ag /MnO achieved 95.7 % Faradic efficiency at -0.85 V vs. RHE, and coupled with long-term stability for electrochemical CO reduction reaction (CO RR). DFT calculations indicated single Ag sites possessed high electronic density close to Fermi Level and could act exclusively as the active sites in the CO RR. As a result, the Ag /MnO catalyst demonstrated remarkable performance for the CO RR, far surpassing the conventional Ag nanosized catalyst (Ag /MnO ) and other reported Ag-based catalysts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202014718DOI Listing
March 2021

Carbon dots as light converter for plant photosynthesis: Augmenting light coverage and quantum yield effect.

J Hazard Mater 2021 05 11;410:124534. Epub 2020 Nov 11.

Key Laboratory for Biobased Materials and Energy of Ministry of Education/Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory of Lingnan Modern Agriculture, Guangzhou 510642 China. Electronic address:

Carbon dots (CDs) with gradient-changed quantum yield (QY) were prepared by regulating the graphitic N and hydroxyl group contents. Then, the QY effect of CDs on plant photosynthesis was studied using chloroplasts and rice plants. After incubation for 2 h in the dark, CDs entered into the chloroplasts and converted ultraviolet radiation to photosynthetically active radiation. By this mechanism, CD1:0.2 (300 μg·mL) with a moderate QY of 46.42% significantly increased the photosynthetic activity of chloroplast (200 μg·mL) to reduce DCPIP and ferricyanide by 43.77% and 25.45%, respectively. After spraying on rice seedlings, CD1:0.2 (300 μg·mL) was evenly distributed in the leaves and resulted in maximum increases in the electron transport rate and photosynthetic efficiency of photosystem II by 29.81% and 29.88%, respectively. Furthermore, CD1:0.2 significantly increased the chlorophyll content and RuBisCO carboxylase activity of rice by 64.53% and 23.39%, respectively. Consequently, significant increases were observed in the growth of CD1:0.2-treated rice, including 18.99%, 64.31%, and 61.79% increases in shoot length, dry weights of shoot and root. These findings contribute to the exploitation of solar energy and agricultural production using CDs in the future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2020.124534DOI Listing
May 2021
-->